During their two-hour debate in Miami last night, Hillary Clinton attacked Bernie Sanders for siding with both the Castro brothers and the Koch brothers.

The Democratic front-runner attacked her rival for being insufficiently critical of George W. Bush and excessively ideological. She also suggested that the Vermont senator was supportive of vigilantes policing the Southern border and auto workers losing their jobs.

So much for pivoting toward Donald Trump and the general election. Clinton’s surprise loss in Michigan seems to have prompted another change-up in her strategy. Her overreaction during the eighth Democratic debate, which was sponsored by Univision and The Washington Post, is one of four reasons that she lost.

CLINTON SOUNDED NERVOUS

1. By throwing the kitchen sink at Bernie, Hillary sounded nervous and even somewhat desperate – certainly more so than she needs to be.

The former secretary of state had some very good moments, connecting with an immigrant who wants to be reunited with her husband and opening up about not being naturally good at politics. But the night will likely be remembered for a stream of over-the-top attacks on her insurgent challenger that undermined the credibility of more effective – and legitimate – hits.

“Senator Sanders … stood with the Minutemen vigilantes in their ridiculous, absurd efforts to, quote, ‘hunt down immigrants,’ ” Clinton said at one point. “No, I do not support vigilantes, and that is a horrific statement and unfair statement to make,” Sanders replied.

Clinton claimed Sanders only criticizes Barack Obama and Bill Clinton. “I wish he would criticize – and join me in criticizing – President George W. Bush,” she said. Bernie is, in fact, a staunch and outspoken Bush critic. The folly of Bush’s Iraq war – which HRC voted for – is a staple of his stump speech. “I gather Secretary Clinton hasn’t listened to too many of my speeches,” he quipped.

But the most disingenuous attack of the night came when Clinton interjected: “I just think it’s worth pointing out that the leaders of the fossil fuel industry, the Koch brothers, have just paid to put up an ad praising Senator Sanders.”

She was referring to a web video released by Freedom Partners, part of the Koch political network, which highlighted Sanders’ opposition to the reauthorization of the Export-Import Bank. Just as Obama did (until he became president), the Vermont senator sees federal government-backed loans to General Electric and Boeing as corporate welfare.

Sanders protested. “There is nobody in the United States Congress who has taken on the Koch brothers – who want to destroy Social Security, Medicare, Medicaid, and virtually every federal program passed since the 1930s – more than Bernie Sanders,” he said in the third person.

Clinton then highlighted Sanders’s opposition to Ex-Im, which she claimed “has helped hundreds and hundreds of companies here in Florida.”

“So from my perspective,” she said, “you sided with the Koch brothers.”

The attack came just a few hours after Vice News posted a story noting that “fossil fuel interests have pumped $3.25 million into the largest super PAC supporting Clinton’s candidacy” and she’s taken nearly $268,000 in contributions from individuals employed in the oil and gas sector so far this cycle. Sanders, who has no super PAC, has received just $35,000 from people in that industry.

There is a tactic in high school debate called “the spread.” It’s when you throw out so many arguments that your opponent cannot possibly respond to all of them, especially with the limited time they have to speak. It’s especially effective when your arguments are just off the wall enough that the other side has not prepared responses ahead of time. Then, when you get a chance to respond to their refutation, you zero in on whatever they “dropped” and hammer them for it, spinning the judges on why it is crucially important to the broader topic being debated. It felt like Clinton was trying to do just that Wednesday night. Alas, this is not a high school debate tournament and the winner is not determined by points or on what competitive debaters refer to as “the flow.”

By coming at him from all sides, Clinton’s overarching message was mushy and discordant. What’s so baffling is that Clinton did not need to go this route. Despite Tuesday’s setback in the Midwest, she’s marching toward the Democratic nomination. Because of her huge margin in Mississippi, she actually received more delegates. Even if she wanted to attack, a lot of this dirty work is best left to surrogates – or even paid advertising.

The Washington Post’s chief correspondent, Dan Balz, calls Clinton’s attack on Sanders for opposing the auto bailout – which she first outlined during the Sunday night debate in Flint and then doubled down on last night – “a stretch at best” and “a deliberate distortion at worst.”

David Axelrod, who was senior adviser to Obama in the White House, felt compelled to weigh in:”The tactic was reminiscent of the campaign’s earlier claim that Sanders wanted to dismantle the Affordable Care Act and leave millions of people without health insurance,” Balz adds, “an argument that, no matter how one feels about his support for a single-payer type system, did not ring true.”

LEFT TURN ON IMMIGRATION

2. Clinton’s lurch to the left on immigration may hurt her in a general election. Pretty much every media outlet, including The Post, leads its coverage of the debate with the candidates taking very liberal positions on immigration to appeal to Latino voters. “In front of an expressive audience at Miami Dade College, each candidate pledged to go further than President Obama to protect immigrants in the United States without proper documentation and to give them a path to achieve U.S. citizenship,” Anne Gearan and John Wagner write.

“I will not deport children. I do not want to deport family members, either,” Clinton pledged, when pressed. “Stop the raids. Stop the roundups.”

As she often has before, Clinton ripped Sanders for voting against the 2007 immigration bill championed by Ted Kennedy.

Sanders alleged that Clinton has changed her position over time. When she was a senator from New York, she opposed drivers’ licenses for undocumented immigrants and she sounded a different tune about the refugee crisis in previous interviews.

While Clinton declined to call Donald Trump a “racist,” she described his support for mass deportation and blocking Muslim immigration as “un-American.”

The fight over immigration could become one of the most significant issues of the general election, especially if Trump is the Republican nominee. Hillary might be thinking about activating the Obama coalition, but coming out against enforcement actions to deal with illegal immigration could make it harder to appeal to some voters.

ON THE DEFENSIVE

3. Clinton was on the defensive for much of the night, facing tough questions and tenacious moderators who followed up when she dodged.

It’s never good when you’re asked about what happens if you get indicted. Asked if she would drop out if the Justice Department filed criminal charges against her for mishandling (retroactively) classified material on her private email server, Clinton said: “Oh, for goodness – that is not gonna happen. I’m not even answering that question.” (She vigorously denies wrongdoing.)

On how her votes in the Senate for a border “fence” are different from the “wall” Trump is proposing: “He’s talking about a very tall wall, right? A beautiful, tall wall,” she joked. “The most beautiful, tall wall – better than the Great Wall of China – that would run the entire border, that he would somehow, magically, get the Mexican government to pay for. It’s just fantasy!” (The Miami Herald called that a shining moment for her.)

On Benghazi: Clinton was shown a tape of the mother of one of the four dead Americans saying she believes Clinton misled her about the attacks – blaming an anti-Islam video, even as she wrote a more honest email to Chelsea. “She’s wrong. She’s absolutely wrong,” Clinton replied, explaining that she said what she believed at the moment she said it. “This was complicated,” she said. (It’s worth noting that moderator Jorge Ramos got booed by the Democratic audience when he brought up the tragedy in Libya, and the crowd cheered Clinton’s response.)

On her refusal to release the transcripts from speeches to Goldman Sachs: “Let’s not kid ourselves. HillaryClinton can release her paid Wall Street speeches now, or wait until the general DoItNow,” Lis Smith, who ran Obama’s war room in 2012 and worked for Martin O’Malley earlier this cycle, wrote on Twitter. “HillaryClinton’s Wall Street speeches are (probably) fairly anodyne. But the longer you wait, the more nefarious they seem. Romney”

SANDERS PUSHES BACK

4. Sanders did a much better job than he has in previous debates at pushing back on Clinton.

Bloomberg’s Mark Halperin gave Sanders an A- and Hillary a B+ on the grounds that he was “consistently more precise and energetic than in the most recent debate”: “Less negative, more natural, more earnest, and more on message than his opponent … He struck many progressive chords that got the audience revved up and cheering. Clinton’s delegate lead looms large, but he showed why he is inspiring tens of millions of liberals across the country.”

Politico’s Glenn Thrush argued that, while nobody won and nobody lost, “There is no more disciplined candidate in the 2016 field than the 74-year-old – none. Sanders’ message discipline allows him to engage in politically expedient character attacks that are the staple of standard-issue negative campaigning – while portraying himself as a class warrior impelled only by principle. Paradoxically, Sanders’ biggest ‘mistake’ of the campaign – saying the American people don’t ‘give a damn’ about Clinton’s email server – has turned out to be one of his canniest moves: The fact that he turned down a free shot at the first debate has given him a permission structure to hammer her relentlessly subsequently.”

To be sure, Sanders came across poorly on his answer about a 1985 TV interview in which he praised Fidel Castro and Nicaragua’s Sandinista government. When moderators played the 30-year-old clip, recorded after he toured South America, Sanders claimed the Castro regime has improved health care and education on the island. “Look, let’s look at the facts here,” he said. “Cuba is, of course, an authoritarian undemocratic country, and I hope very much as soon as possible it becomes a democratic country. On the other hand, it would be wrong not to state that in Cuba they have made some good advances in health care. They are sending doctors all over the world.”

The Clinton campaign pounced, tweeting that Sanders has refused to “disavow praisew for Fidel Castro.”

THE BOTTOM LINE

Democrats are headed for a long slog. Dan Balz explains: “A few days ago, Wednesday’s debate here appeared as if it might be an anticlimax as Clinton rolled toward the nomination. Instead, Sanders arrived reenergized and reinvigorated after his surprising victory in Michigan. Rather than questions about Sanders’s viability, Clinton faced questions about what had gone wrong with her campaign. … Whatever transpires from here, this is not the campaign Clinton envisioned. She remains the favorite to win the nomination. Michigan did not change that. But because of that vote, she faces renewed doubts about her effectiveness as a candidate.”

There are contests next Tuesday in Florida, Illinois, Missouri, North Carolina and Ohio. A Washington Post-Univision News poll conducted on the eve of our debate found that Clinton leads Sanders 64 percent to 26 percent among likely Democratic primary voters in Florida. A victory that big in a state as big as Florida could help move the narrative back in her direction.